[Elecraft] KPA1500 replacement devices

[N2TK, Tony]

What are the current part vs. the original part number in the 1500?
N2TK, Tony

Sent from my iPhone

> On Nov 1, 2022, at 6:23 PM, M Cresap via Elecraft <elecraft at mailman.qth.net> wrote:
> 
>  Hi Hal
> I see the Rds difference. Wouldn't the higher Rds be compensated by the better Rth (thermal resistance from junction to case) spec in the ART devices?
> 73, Mike, W3IP
> 
>    On Tuesday, November 1, 2022 at 03:15:09 PM EDT, Dynolab <dynolab at comcast.net> wrote:  
> 
> While the higher voltage ratings of the ART1K6 or ART2K0 series looks very
> attractive, it is extremely important to remember that heat is the number
> one killer of LDMOS RF power FETs!
> That being said, take a look at the specifications of the ART1K6 and ART2K0
> and note that the Rds(on) drain-source on-state resistance of these devices
> is significantly higher than that of the devices presently being used in the
> KPA1500.
> And this higher Rds(on) would result in higher drain-source saturation
> voltage when the amplifier is running near its limits which would in turn
> result in higher heat dissipation.
> It is therefore possible that the ART1K6 or ART2K0 devices may be less
> reliable than the devices currently being used in the KPA1500.
> 
> 73,
> Hal
> W7YNC
> 
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of M Cresap via Elecraft
> Sent: Tuesday, November 01, 2022 10:21 AM
> To: Elecraft at mailman.qth.net
> Subject: [Elecraft] KPA1500 replacement devices
> 
> Anyone have an educated guess whether the ART1K6xx or ART2K0xx devices would
> be a drop in replacement for the currently used device in the KPA1500? Most
> of the interesting specs are within 10% of the current device, the open loop
> gain may be a dB or two higher (if the data sheets are really comparing
> apples to apples). 
> 
> The main attraction of the ART1K6 and ART2K0 devices is the higher peak
> voltage handling capability - 177 or 200 volts vice 135 volts for the
> current device. Maybe a higher peak voltage capability will keep the
> amplifier out of the repair shop due to external events like arcing baluns
> or antennas flexing in the wind.
> 
> The package styles are identical, the ART devices are in stock from a few of
> your favorite distributors, similar price to the current device, maybe the
> quiescent bias voltage would have to be tweaked a bit...
> 
> 73, Mike, W3IP
>   
>   -    
> 
> 
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